Explosions continue on fourth day of Nairobi Mall massacre

September 24, 2013, 8:04 AM|As Kenyan security forces secure the perimeter of the mall, gunfire and explosions are still erupting inside the building. The country's foreign minister says the terrorist group al-Shabab is responsible for the bloody siege and Americans are among the attackers. CBS News correspondent Charlie D'Agata reports from Nairobi.